The existing matching filter group-based method for FSK/GFSK demodulation mainly accomplishes a demodulation operation in a complex domain (i.e. I\Q plane), which requires a large number of complex multiplication, complex addition and complex subtraction operations, resulting in a system with high complexity.
Since an FSK/GFSK signal has a constant envelope, if the digital information transmitted is all contained in the phase of the signal and the demodulation operation is accomplished in the phase domain, a large number of complex operations could be converted into real addition and subtraction operations, and thus system complexity may be effectively lowered.
However, the inventors find that the existing phase domain demodulation technology does not employ a phase matching filter group (i.e., the phase matching vector group in the invention) for the demodulation operation, or there exist technical defects in employing a phase matching vector group, so that the performance of the existing phase domain demodulation technology is much lower than that of the complex domain demodulation technology.